The seven -- four men and three women -- were climbing or skiing when the avalanche, an estimated 30 metres wide and 600 metres long, hit on a western slope of the 2,860-metre-high Mt Masago, police said.
They were taken to hospital by helicopter but were confirmed dead, police said.
A local police officer said rescuers were continuing the search as it was not clear if there were any other people on the mountain at the time of the avalanche.